2004 INFINITI FX45 smart key will need to be programmed to your vehicle before it will work for you. Programming can only be done at an automotive locksmith shop or your local Infiniti dealership. There are no onboard programming instructions for 2004 INFINITI FX45 smart keys. They can only be programmed using special diagnostic equipment. This smart key comes with battery and is tested for functionality before sending. Emergency key sold separate.